Anal fissure

Anal fissure is an unnatural crack or tear in the anus, usually extending from the anal opening and the midline of the anus. Anal fissure is usually shallow (less than a quarter of inch or 0.64 cm deep).


Most anal fissures are caused by stretching of the anal sphincter muscle beyond its capability. Various causes of this fissure include:

  • straining to defecate, especially if the stool is hard and dry
  • severe and chronic constipation
  • severe and chronic diarrhea
  • Crohn's Disease
  • rough anal sex
  • insertion of foreign objects into the anus
  • spastic tight sphincter muscles
  • Anal fissure is common in women after childbirth and in infants.


The symptoms of anal fissure include:

  • Pain during, and even hours after, defecation
  • Visible tear in the anus
  • Blood in stool or on toilet paper
  • Constipation


A large majority of fissure are shallow or superficial fissure. These fissures self-heal within a couple of weeks. While waiting for the fissure to heal, topical or suppository containing anti-inflammatory agents and local anesthetic can be used. Furthermore, treatment used for hemorrhoid such as eating a high-fiber diet, using stool softener, taking pain killer and sitz bath can help.

Anal fissure in infant usually self-heal without anything more than frequently changing diapers.

Deep fissures, on the other hand, may require surgery. These painful fissures cut through the sphincter muscle thus making it prone to spasm, which exacerbates the fissure and aborting the healing process. Surgical procedures for deep anal fissure are:

  • Anal dilation or stretching of the anal canal.
  • internal lateral sphincterotomy or excising a portion of the sphincter.
  • Despite the high success rate of these surgical procedures (~95%), there are potential side effects, which include: risks from local anesthesia, infection, anal leakage or fecal incontinence.
  • Medications can also be prescribed. Nitroglycerine and nifedipine ointments can relax the sphincter muscle, thus allowing the healing to proceed. Botulinum toxin injection can also be used to relax the sphincter muscle.


In infants under one year old, frequent diaper change can prevent anal fissure. For adults, the following can help prevent fissure:

  • Treating constipation by eating food rich in fiber, drinking a lot of water, and taking stool softener
    Treating diarrhea promptly
  • Lubricating the anal canal with petroleum jelly
  • Avoiding straining or prolonged sitting on the toilet
  • Using a moist wipe instead of perfumed and harsh toilet paper.
  • Keeping the anus dry and hygienic.
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